Electric switchgear



Jan. 3, 1950 Filed March l5, 1948 4 sheets-sheet 1 rzvenlor Ian. 3, 1950 yD. A. J. oxLEY ELECTRIC SWITCHGEAR 4 Sheets-Sheet 2 Filed March l5,A 1948 Jan. 3, 1950 D. A. J. OXLEY 2,493,689

ELECTRIC SWITCHGEAR Filed March l5, 1948 l 4 Sheets-Sheet 3 H 0/ FGF- o J l J f, l I I 'F4 F I y 5 f s L 22 2f L 4, o I F2 E5 o .f G4 ,W 02

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Inventor Doug/as Ox e- Atorneys Jail.. 3, 1950 D. A, J, OXLEY 2,493,689

ELECTRIC SWITCHGEAR Filed March l5, 1948 4 Sheets-Sheet 4 F/GZ C2 Y l, c5 l C/ A 2 F/Ge A/C H A Kl x o K Douglas A. Oxley Patented Jan. 3, 1950 Douglas Arthur James Qxl'ey, Banbury, England` Application March 15, 1948, Serial No. 14,922 In Great-Britain March .211, 194.7

11 Claims.

This invention relates. to electric switchgear of the type in which the moving contact is carried at one end of an arm pivoted at its other end to move about an axis substantially perpendicular to the length of the arm. Such switchgear is Widely used under external conditions for high voltage isolating switches and the like.

To enable large currents to be efficiently conducted it is generally desirable to employ high contact pressure, and in addition it may, on occasion, `be necessary tov separate the contacts when they have been bonded together by a layer of ice. As the arm may be several feet in length the torque required to overcome any considerable resistance to separation of the contacts may be very substantial, and it must be borne in mind that the fixed contact, and the pivot of the moving arm, will be mounted on high voltage insulators of limited'` mechanical strength.

It has therefore been proposed to provide means forproducing a small initial relative movement between the contacts to free them from one another before starting the main movement of the arm about its pivotal axis. One type oi ini-tial movement consists of twisting the arm about its longitudinal axis, and the present invention is concerned with the provision of improved mechanism for this purpose.

According to the present invention, operating mechanism for electric switchgear of the type 'speced comprises mechanism for producing a twisting movement of the arm, followed by movement of the arm about its pivot, such mechanism being totally enclosed within a casing surrounding the pivot.

In one formv of the invention, the mechanism comprises an operating shaft about the axis of which the arm pivots, a member secured' to the shaft and spaced from it in a direction substantially parallel to the arm, and engaging a member secured to the arm and spaced from itin a direction substantially parallel to the shaft, together with stops for limiting the twisting movement of the arm.

In order to balance the thrusts, a symmetrical arrangement may be employed comprising two opposed members spaced from the shaft in opposite directions parallel to the length of the arm and on opposite sides of the arm, and engaging two opposed members spaced from .the arm in opposite directions parallel to the shaft and, on opposite sides of the shaft. Y

Preferably, the arrangement also includes an interlocking member secured to the arm and spaced from it. in a direction substantially per! pendicular to the axes both oi the, shaftv and 01 the arm, and confined in an L shaped slotin a lixed part so that in the opening vmovement -it prevents pivotal movement ofthe `arm until .the predetermined twisting. movement is completed and viceversa when closing.

The invention may becarried into practice in various ways, but. one specific embodiment .will now be described by way of example, with refer-A ence. to the accompanying drawings, in which:

Figure 1 is a plan view of anisolating switch, partly in section;

Figure 2 isan end. view of one of the .movable contacts; Y Y,

Figure. 3. is a side elevation, partly in section on the line 3-3 of Figure 1, showing detailsof the pivot, mechanism;

Figure 4v is an end elevation in section on the lineA-A of Figure l, showing details of the pivot mechanism; f

Figure 5 is a plan view in section on the line 5 5 of Figure, 4, showing details of the pivot mechanism;

Fig-ure 6 is an elevation in section on the line 6--6 of Figure 1, showing details of the actuating mechanism; f i- Figurey '1 is aside elevation showing the outer casing andthe anchoring means of the embodiment, and

Figure 8 is a diagram on a smaller scale showing the genera-l layout of the-switch, Y

In this. embodiment of the invention the con-v tact arm A carrying its moving contacts A1v andA2 is arranged to pivot at its-end aboutl a horizontal axis perpendicular toits length-in a fixed-bearing provided `by a fork B-mounted on top-of an insulater C.` The fork supports. bearings for-apair of trunnions or stub shafts D1 and D2, one of which D1 constitutes an operatingl shaft.

Asfshown in Figures 3 and 6, an operating insulator E, arranged-to rotate with its axis substantially vertical, has mounted on its upper end a Vmetal bosslii1 which can rotate in a bearing forming part of a plate C1 extending from the comnanion insulator C. A cap E2 is bolted toV the boss E1 and carries ahorizontal arm E3 Vpivoted at its `outer end to one end of a link E4. The link E* is pivoted at its other end to anv arm E? carried by the operating shaft D1 and rigidly secured -to it. Accordingly, if the lower end ci the operating rinsulator E is rotated by' mecha,- nism at earth potential, the trunnion D1 consti- .tuting the operating shaft will be rotated. The

' 3 plate C1 serves to relieve the insulator E of stresses other than pure torque.

The two trunnions or stub shafts D1 and D2 are firmly secured in diametrically opposite points of an inner ring F1, mounted as shown in Figures 3, land 5 with its axis substantially coincident with that of the contact arm A. The ends of .these stub shafts project through the inner ring into diametrically opposite holes ina sleeve F2 which is thereby pivoted so that it can move about the axis of the operating shaft D1.

The contact arm A carries an outer ring F3 rigidly secured to it with its axis approximately coincident with that of the operating shaft D1. Both the inner ring F1 and the sleeve F2 are Within the outer ring F3. Projecting from one.'

face of the outer ring F3 is a pair of lugs-constituting a fork F4 between which extends a ballended arm F5 projecting from one face of the inner ring F1. The centre of the ball lies approximatelyin the plane containing'the axes ofthe operatingshaft D1 and of the contact arm A, from'both Vof which, it is approximately equi- 'distantg The ball-ended arm on the inner ring F1 and the fork F1V on the outer ring F3 co-operate in the mannerl of a pair of bevel gears so that if the operating shaft, and with it the inner ring, is turnedyitwill tend'to rotate .the outerringand hence the contact arm, about the xisiof the latten Y y In order to balance thrusts, a second ball-ended arm F5 is provided projecting from a diametrica llywopposite pointof the opposite .face of the inner ring F1, and engages a second forlfli4 projecting from Vavdiametric-ally opposite point of the opposite faceof the outer ring F3, asshown in Figure 5. y n

In ordertoensure the correctsequence of movements, the outer ring F3 carries av pair of interilocking members in the form of square proJ'BC- tionsdF6 placed at diametrically opposite points cir-thef outer ring', and spaced from the intersection of the axes of the contact arm Aand the operation vsliaqft D1, in a direction perpendicular to both theseaxes., Theprojections Fiflt into a pair of L-shaped slots G1 in a fixed hollow, cylms? @Carried by ceca-rm .0i .the fork B- YWien thev switchisln theclosecl position, each of the projections F6 is at one end ofv the'baserQfAitsslot G1 which lies parallel to the axis Yof the operating shaft D1. AccordinglyZ the nouterring F3 isprevented froms moving pivotally about the 'axis of the:V operatingshaft D1 andfjcanonlyjnove about theaxis of the contact' arm A. Due tothe Vbevel action of me ban-encedarms' andthe'forks F2,V such aV twisting movement about the axisV of the contact arm loccursuntil the projections F' reachtheanglesfof the Lf-shaped slots G1. Further twisting motion is then prevented and thereafter continued movement of the operating shaft D1" about its'axi'sfproduces bodily movement of the conta-'ct arm Atogether with theI outer and inner rings F3 and'F1 about t'hfe'axisl of the Aoperatin'g'sli'aft 'D1.` U('Joll'versely,V when the switch is contact A1 'or A2 enters.

its

bein'g `close `d `byturningwthe operatingn nshaft D1 iltlienopposite directionpno twisting movement can occurftuntil the axis of the contact 'armA is in its fully closed position.- The yfixedcylinder G has acircumferential slot inV it through, which the contact arm A projects,A Y t j 't The cylinder G has been described as fixed, but itiSPrefeired that it should be resiliently secured soas to be capableof slight movement to accomone end by a disc G2 carried by a sleeve G3 which surrounds the trunnion D2 and acts as a bearing within which the trunnion can rotate. The sleeve itself can rotate in a bearing provided by one arm of the fork B, and carries at its outer end an arm G4, the end of which is secured, as shown in Figure 7, through a resilient link G5 to lugs C2 forming part of the plate C1. Adjusting screws G3 Yallow the limits of travel of the contact arm A to' be accurately controlled.

The hollow cylinder G is surrounded by an outer casing H comprising two dish-shaped pieces Y boltedtogether to form a closed cylinder. The

outer casing H has holes which allow it to fit closely round the bearing sleeve G3 and round a ,corresponding bearing sleeve I for the operating V shaft D1, and a hole registering with a radial sleeve H1 which fits round the contact arm A. Accordingly, the operating shaft D1 and the contact arm A are capable of rotating slightly in relation to the outer casing during twisting movement', while during pivotal movement the outer casingI-I moves bodily with them about the axis of the operating shaft.

For lubrication purposes, grease cups J are provided at the bearings of the trunnions D1 and D2 and'of the insulator boss E1 in the plate C1.

' The fixed contacts K1 and K2 are of the form shown in Figure l, `each comprisinga pair of resiliently mounted blocks between which the moving Figure 2 shows a crosssection of the moving contactr A1 or A2, which willidescendv into the space between the fixed contacts K1v or K2 with its-greatest width vertical or approximately so, and will then be twisted so 'as-to; tend to separate the fixed contacts and ensureaihigh-pressure contact. The pairs of fixed contacts K1 and-'K2 areopen'at the Vbottom so as to prevent the 'accumulation'of ice or snow. f The-'interlocking arrangement described provides means' for Vlocking the moving contact in the closedrposition'Y and `'preventing itv from being blown out bythe magnetic effect of current surges. -The outer casing Hhas-in it only three holes, namely for the two4 trunnions D1 and D2 and the contactV arm A; which Yare 'in-'every casel afclose fit and can'be sealed satisfactorily, Vsince no relative movementv occurs` except-a limited rotary movement. vvAccordingly, all themechanical parts liable to cause trouble by the flong exposure to Vwhich -externalV switchgear is subjected, are enclosed within the outer casing and are protected yfrom such fadverseconditions. This applies equally to the stops by-which the twistingV movement and pivotal movement are limited, so that the correct engagement of theseY stops cannot-be 'interfered' with by 'the presence, for example, of

yice and'snow. Y 1

YThe mechanism, in addition to being protected from external influences, has a low' moment of inertia thereby facilitating the. opening and clos- .ingoftheswitch f Y n l -v l VPreferably the operating mechanism by which the operating shaft is turned includes a resilient member tending to moveV itslightly-beyond the closed position. This is particularly advantageous in thecase cfa switch-.having several poles or .phaseswhich are operatedsimultaneously, where satisfactory completionr of the .twisting movementmight otherwise be interfered with by slight lack .of adjustment or alignment between one phase and another. A

WlfiatI claim as my inve tion and desire to secure by Letters Patent is:

niodateshocks.' For this purpose it is closedV at 75 `1f. ruectrie switchgear including an arm pivoted aty one endt'o,` moveabout a transverse pivotal axis substantially' perpendicular -to its-length, amoving Contact carried by the arm near its/other end,- mechanism f'or producing a twisting movement'ofthe arm about'its longitudinalI axis followedr by a swinging movement about its transverse'pivotal axis, such mechanism including anoperating shaft coaxial with the saidtransverse pivotalv axis of the) arm, interengaging members one secured to-theshaft and spaced from it in a dlrection'substantially parallel tothe lengt-hof the arm, andi the other secu-red'to the' arm and spaced from it in a direction substantially parallel to the shaft.

2. Electric switchgear including an arm pivoted at one endw t`o move about atransverse pivotal axis substantially perpendicular to its length, a moving Contact carriedV by' the arm near its other end, mechanism for producing a twisting movement ofthe arm about its longitudinal axisl followed by a swinging movement about its transverse pivotal axis including an operating shaft coaxial with the saidL transverse pivotal axis of the armginterengaging members one secured to the'- shaft andv spaced from it ina direction' substantially parallel to the length of the arm, and the other secured to the arm and spaced from it in a direction substantially parallel to the shaft, and a casing totally enclosing such mechanism.

3. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, mechanism for producing a twisting movement of the arm about its longitudinal axis followed by a swinging movement about its transverse pivotal axis including an operating shaft coaxial with the said transverse pivotal axis of the arm, interengaging members one secured to the shaft and spaced from it in a direction substantially parallel to the length of the arm, and the other secured to the arm and spaced from it in a direction substantially parallel to the shaft, and interlocking means serving to prevent swinging movement until the twisting movement is completed when opening, and to prevent twisting movement until the swinging movement is completed when closing the switch.

4. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, mechanism for producing a twisting movement of the arm about its longitudinal axis followed by a swinging movement about its transverse pivotal axis, such mechanism including an operating shaft coaxial with the said transverse pivotal axis of the arm, two interengaging pairs of members including two opposed members secured to the shaft and spaced from it in opposite directions parallel to the lengths of the arm and on opposite sides of the arm, and two opposed members secured to the arm and spaced from it in opposite directions parallel to the shaft and on opposite sides of the shaft.

5. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, mechanism for producing a twisting movement of the arm about its longitudinal axis followed by a swinging movement about its transverse pivotal axis, comprising an operating shaft coaxial with the said transverse pivotal axis, an inner ring substantially coaxial with the arm and coaxial withy the operating shaft and securedY to the arm, andat least one pair of interengaging members carried respectively by the outer andinner rings and engaging one another at a position spaced fromV both the longitudinal andi transverse pivotal axes of the arm but adjacent tothe plane containingthose axes.`

6; Electric'switchgear including an arm pivoted at one end' to :move about a transverse pivotal axis substantially perpendicular to its length,` a moving'contaot carried by the'arnrnearitsother end; mechanism for prcducingfa twisting movement of the armabout its longitudinal axis followed by a. swinging movement about its transverse pivotal axis,v comprising an operating shaft coaxial` with thel saidE transverse pivotal axis, an inner ringsubstantially coaxial-with the arm and secured to" the operating shaft, a sleeve pivoted in the inner ring about the transverse pivotal axis and receiving the arm which-i can turn in it about its long-itudinal axis', an outer ring substantially coaxial-- with the operating shaft and secured to the arm, and at least one pair of interengaging members carried respectively by the outer and inner rings and engaging one another at a position spaced from both the longitudinal and transverse pivotal axes of the arm but adjacent to the plane containing those axes, and interlocking means serving to prevent swinging movement until the twisting movement is completed when opening, and to prevent twisting movement until the swinging movement is completed when closing the switch.

7. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, mechanism for producing a twisting movement of the arm about its longitudinal axis followed by a swinging movement about its transverse pivotal axis, comprising an operating shaft coaxial with the said transverse pivotal axis, an inner ring substantially coaxial with the arm and secured to the operating shaft, a sleeve pivoted in the inner ring about the transverse pivotal axis and receiving the arm which can turn in it about its longitudinal axis, an outer ring substantially coaxial with the operating shaft and secured to f the arm, and at least one pair of interengaging members carried respectively by the outer and inner rings and engaging one another at a position spaced from both the longitudinal and transverse pivotal axes of the arm but adjacent to the plane containing those axes, and a casing totally enclosing such mechanism.

8. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, an operating shaft coaxial with the said transverse pivotal axis, mechanism operated by the said shaft for producing a twisting movement of the said arm about a longitudinal axis followed by a swinging movement about its transverse pivotal axis when opening the switch, and a casing totally enclosing such mechanism.

9. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, an operating shaft coaxial with the said transverse pivotal axis, mechanism operated by the said shaft for producing a twisting movement of the said arm about a longitudinal axis followed 'by a swinging movement about its transverse pivotal axis when opening the switch, and interlocking means serving to prevent swinging movement until the twisting movement is completed when opening and to prevent twisting movement until the swinging movement is completed when closing the switch, and a casing totally enclosing such mechanism.

10. Electric switchgear including an arm pivoted at one end to move about a transverse pivotal axis substantially perpendicular to its length, a moving contact carried by the arm near its other end, an operating shaft coaxial with the said transverse pivotal axis, mechanism operated by the said shaft for producing a twisting movement of the said arm about a longitudinal axis followed by a swinging movement about its transverse pivotal axis when opening the switch, and interlocking means serving to prevent swinging movement until the twisting movement is completed when opening and to prevent twisting movement until the swinging movement is completed when closing the switch, such interlocking means comprising an interlocking member secured to the arm and spaced from it in a direction substantially perpendicular to the axes both of the shaft and of the arm, and a stationary part formed with a slot in which the interlocking member is confined, the slot being L-shaped in a plane parallel to the plane containing the axes of the shaft and of the arm.

11. Electric switchgear as claimed in claim 10 in which the stationary member formed with the L -shaped slot is anchored by resilient means.

DOUGLAS ARTHUR JAMES OXLEY.

REFERENCES CITED The following references are of record in the ille of this patent:

Y UNITED STATES PATENTS 

